Martin Daniel Appel took center stage yesterday in the Easton courtroom of Northampton County Judge Robert A. Freedberg, pleading guilty to the murder of three women during the bloody June 6 robbery of the East Allen Township branch of First National Bank of Bath.

Several previously unreleased details about the robbery and killings came to light during yesterday's court session.

Appel, whose 28th birthday falls on Aug. 1, was escorted to the heavily guarded courtroom from the county prison by sheriff's deputies. Dressed in a three-piece pin-stripe gray suit, a light blue shirt, wine-colored tie and black patent military-style shoes, and wearing the thick-lensed, black-framed glasses he has worn in previous court appearances, he appeared calm, even relaxed, as he stood before Freedberg.

Most of his answers to questions posed by the judge were simple,"Yes, Your Honor," and "No, sir" replies.

Appel, accompanied by Assistant Public Defenders Ellen Kraft and Lorenzo Crowe, assigned to give him legal advice when he expressed his wish to represent himself, indicated during the proceedings that he will not testify against co-defendant, 28-year-old Stanley Hertzog of Allentown.

Assistant District Attorneys Anthony Blasco and John F. Spirk Jr. said his decision will not affect their prosecution of Hertzog, because they have prepared the case on the assumption that neither man would testify.

During the proceedings, facts about the murders, previously unreleased, were provided by Spirk as he outlined the facts of the case. Included was the information that all three of the women who died were killed by bullets from Appel's gun, not Hertzog's.

Spirk also said Appel shot 34-year-old customer relations representative Jane Hartman of North Catasauqua four times, at close range, as she huddled under her desk, and that when he determined that 48-year-old teller Janice Confer of East Allen Township was still alive after the first volley of shots, he shot her again.

Spirk also noted that Appel gave Hertzog a chance, which he didn't take, to back out of the robbery and killings, planned for about a month, shortly before they entered the bank.

Besides the three murder charges, Appel pleaded guilty to a total of 16 other charges, including two counts of attempted first degree murder (of bank manager Marcia Hauser of Nazareth and bank customer Thomas Marchetto), two counts of aggravated assault, one count each of robbery, burglary, criminal mischief and making terroristic threats, and eight counts of conspiracy.

At one point in the proceedings, he told Freedberg, "If it could be permitted, I would like to plead to first degree murder," a crime which carries a sentence of either death in the electric chair or life in prison.

However, Freedberg told Appel, who is acting as his own attorney, that a state court ruling prohibits the entry of a guilty plea to first degree murder. A plea may be made either to a general charge of homicide, which covers three degrees of murder and two degrees of manslaughter, or, as Appel did, to a general charge of murder, which covers only the degrees of murder.

Freedberg told Appel, "I understand your desire and you will have an opportunity to express that at the degree of guilt hearing," which he set for 9 a.m. Aug. 7.

Several times during the proceedings, which lasted more than an hour, Freedberg stressed to Appel that he was making "a critical decision . . . in terms of your own life," and told him, "I must make sure you understand you're subjecting yourself to the possible imposition of the death sentence." Appel indicated he understood.

Statements Appel has made at previous court appearances, and a sentence in the handwritten statement he asked Kraft to distribute yesterday to the local media, have indicated that Appel wishes to die in the electric chair.

In the statement, in which he thanks State Trooper Charles Marshall, who filed the charges against him, the assistant district attorneys handling the case, and Kraft and Crowe, Appel says, "I feel that only by my death can I somewhat atone for the deaths of the others."

Blasco yesterday repeated that the prosecution will seek the death penalty for both Appel and Hertzog. He said the Commonwealth may present more than 30 witnesses - "our whole case" - at the degree of guilt and sentencing hearings, which will be heard by Freedberg, since Appel waived his right to have a jury hear testimony and rule on his sentence.

Blasco also said, "I'd like to put him in the chair myself. If any case deserves death, this one does."

Spirk outlined the facts of the case for Freedberg yesterday, bringing to light several aspects of the case which could not be made public before the plea was entered.

Spirk confirmed that all of the bullets that caused the deaths of 48-year- old Janice Confer of East Allen Township, 55-year-old Hazel Evans, of Coplay, and 34-year-old Jane Hartman of North Catasauqua, came from Appel's gun, a 9-mm automatic which had a 14-shot clip.